Ensiling water hyacinth for enhanced biomethane production: effect of co‐ensiling with maize straw and eggshell powder as additive

Abstract

AbstractBACKGROUNDThe invasion of water hyacinth (WH) on water bodies comes with adverse consequences for humans and the environment. Using WH as a substrate for affordable and clean energy production is one way of controlling the invasiveness of the aquatic plant. In this study, ensiling was carried out with and without the addition of maize straw (MS) and eggshell powder (ES) to determine the effect of higher total solids (TS) and butyric acid contents on the biomethane potential (BMP) of WH. The silages were stored at ambient temperature for 210 days. The kinetics of biomethane production was determined using three different kinetic models.RESULTSEnsiled WH without MS and ES had a reduced BMP after 210 days. However, a combination of higher TS (40%) and butyric acid contents, resulting from the addition of MS and ES, significantly increased the BMP of WH by 64% after 210 days of ensiling. The kinetic study showed that the dual‐pool kinetic model described the BMP of ensiled and co‐ensiled WH better than the first‐order and modified Gompertz models.CONCLUSIONSIncreasing TS and butyric acid contents by co‐ensiling with MS and ES is a low‐cost and sustainable method of enhancing biomethane production from WH. In this way, the invasive nature of WH can be effectively controlled (since a large quantity can be harvested and stored) and circular economy can be enhanced through the effective utilization of waste. © 2022 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).